Reproducing machine



June 2, 1931. c. KREBS REPRODUCING MACHINE 2 Sheets-Sheet l Filed Sept. 14, 1929 June 2, 1931. c. KREBS REPRODUCING MACHINE 2 Sheets-Sheet 2 Filed Sept. 14. 1929 I Patented June 2, 1931 PATENT OFFICE CARLOS KREIBS, 013 BOSTON, MASSACHUSETTS REPRODUCING MACHINE Application filed September 14, 1929. Serial No. 392,723.

This invention relates to an improvement in reproducing machines in which a tool, for example, a cutting torch, is controlled by the movement of a tracer or equivalent member over a pattern, such as a template.

My invention contemplates a very great simplification of machines of this class by the utilization in connection with a movable carriage of parallel motion linkage having few parts yet capable of improved accuracy of operation and adapted to control heavier tools or a larger number of tools than the linkages of previous comparable machines. Accordingly primary objects of my invent-ion are concerned with an increase in the sim-. plicity, accuracy and capacity of machines of this type.

The parallel motion linkage of certain types of reproducing machines tend to develop inaccuracies due to the failure, generally because of lost motion, of certain parts of the linkage to move absolutely in unison. My invention is intended to remedy this, and. accordingly a further object of my invention is to provide means for insuring movement in absolute unison of certain parts of the linkage, independently of the presence of lost motion between the main members of the linkage.

My invention also comprises a construction a in which inaccuracies in the movement of the tool due to distortion of the tool supporting means are diminished by a proper balancing of the various elements of the machine-and attainment of this result constitutes another object of my invention.

Other objects of this invention reside in the details of construction hereinafter set forth as will be apparent to one skilled in the art from a consideration of the following specification taken in connection with the drawings which form a part thereof, and in which: I I 3 Fig. 1 is a plan view of an embodiment of my invention; I

F ig. 2 is a side elevation of the machine of Fig. 1 with certain of its parts omitted for clearness of illustration;

Fig. 3 is a section on the line 33 of Fig.

Fig. 4 is a section on the line 4-4 of Fig. 1

Figs. 5, 6 and 7 show modified forms of mechanism for insuring equal movement of members of the parallel motion linkage;

Fig. 8 is a plan view of another apparatus in which certain aspects of my invention are embodied;

Figs. 9 and 10 are side and plan views showing the connection between lateral links and the gear wheels of Fig. 8, but on an enlarged scale; and

Fig. 11 is a plan view of the central portion of a machine similar to that of Fig. 8, but provided with one of the alternate forms of connection between the two gear wheels of the machine. v v

In the embodiment of the invention shown in Figs. 1 to 4 the machine is provided with a main platform carriage 11, adapted to move along a track 12. Mounted on this main carriage are two spaced vertical pivots 14 and 14, having parallel axes, and upon which the two longitudinal arms 15 and 15 constituting links of a parallel motion device, are respectively rotatably mounted by means of antifriciton bearings 16 and 16. The arms 15 and 15 are pivotally joined, preferably at their ends, by lateral links 19 and 20, to form a closed parallelogram of which the non-adjacent arms 15 and 15' are pivoted to the main carriage by the pivots 14 and 14'. Lateral link 20 is extended on either side of this parallelogram to support one or more tools such as the cutting torches 21which are adjustably mounted on link'20 and/or an-angularly adjustable bracket 22.

A template follower device comprising a. tracer indicated at 24 is mounted upon one of the links of the parallel motion device, and preferably upon the same link 20 that supports the tools. 7

In order to utilize the space within tracks 12 to accommodate a template, I prefer to mount tracer 24 upon link 20 between arms 15 and 15. The tracer may be moved in contact with a template manually or by means of a suitable tracer actuating mechanism, indi-' cated by the numeral 26 and preferably of the type described in my copending application Serial No. 288,023, filed June 25, 1928.

I prefer to equalize the strains in the various elements of the linkage and to equalize the weight of the movable system with respect to thetwo pivots 14 and 14, and accordingly I have provided means for accomplishing these results. In the machine of Fig. 1, this function is performed by two weights 30 and 31. Weight 30 is adjustably mounted upon one of the links, which Iprefer to belink 20, and serves to'balance laterally of the machine, the weight of the tool or tools and the tool-supporting portion oflink20. VVeight31 is adj ustably mounted on the opposite side of the linkage from the tracer 24 and tools 21 for balancing the weights of these members with respect to the pivots 14 and 14'. By thus balancing the system and equalizing the strain on the opposite sides thereof I have obtained a parallel motion linkage in which variable distortion in operation is greatly minimized.

Although the whole system of linkage thus far described is linked for parallel motion, and is capable of utility, I prefer to increase the accuracy and sensitiveness of the apparatus by providing means for causing the spaced arms 15 and 15 to swing about their pivots in unison, independently of lost motion between the links of the parallelogram. In the device of Fig. 1, this result is accomplished by providing each of the arms 15 and 15, coaxially with their respective pivots 14 and 14, with rigidly attached rotary members, illustrated as gear wheels 41 and 41, and kinematically connecting these gear wheels, and consequently the arms 15 and 15, independently of the linkage, for movement in unison. In Fig. 1, I have shown connecting means for the gear wheels which comprises the two rack bars 42 and 43 held in close movable contact with gear wheels 41 and 41' by a series of vertical rollers 45, a series of horizontal rollers 46, and guiding sleeves 47. By means of this construction the rotary motion of each of the gear wheels is communicated to the opposite gear wheel, and the two arms 15 and 15 are caused to move in llIllSOIl.

In Figs. 5, 6 and 7, I have shown alternate means for kinematically interconnecting the two arms 15 and 15' for the same purpose. Fig. 5 shows rotary double cranks 50 connected to the arms 15 and 15" at their pivots and connecting rods 51 and 52 joining the corresponding cranks. The provision of double cranks prevents the occurrence of any dead center.

Fig. 6 illustrates rotary bevel gears 60 attached to the arms 15 and 15 over their pivots, and the two bevel gears 60 operatively connected by a rotatable shaft 61 carrying bevel gears 62.

Fig. 7 illustrates a form of connection in which rotary helical gear wheels are attached to arms'15 and 15 and the two gear wheels operatively connected by shafts 71 carrying helical pinions 72.

In the operation of the machine of Figs. 1 to 7, the tracer 24 is, moved either automatically or manually in contact with a template having the desired configuration of the finished article. Preferably this template is located between the rails of track 12. The parallel motion linkage described above communicates the motion of the tracer 24 to the various tools 21 and enables them to produce replicas of the template. Movements of the tracer around a template of any desired shape are permitted by the combination of the movement of the carriage 11 on the track 12 and of the approximately lateral movement of the arm 20 as restrained by the parallel motion linkage.

In Figs. 8 to 11 the aspect of my invention which comprises providing means for insuring movement in unison of two of the portions of the linkage independently of lost motion between the main members of the linkage, is illustrated as embodied in an improvement to a reproducing mechanism of the type described in my copending applica tion Serial N 0. 347,065, filed March 14, 1929. In the above copending application I have described a reproducing device comprising a movablymounted base illustrated in Fig. 8 of the present application by the numeral 121, a pair of platforms 110, and pairs of carriages 112, 112 and 113, 113 which respectively support a tracer and a reproducing tool such as a cutting torch. The carriages 112 and 112 are joined by a cross beam 115 and the carriages 113 and 113 are similarly joined by a crossbar 117 so that each pair of carriages moves as a unit. A tracer 150 is carried by the cross beam 115 and a plurality of reproducing tools indicated by the numerals 200 are supported at desired points upon the crossbar 117 or its lateral egtensions.

Suitable transmission means are provided on each of the platforms 110 for causing the carriages 112 and 113 to move over the platform 110 to the same extent but in the reversed direction. This transmission means comprises a pair of rack bars 206 and a gear 207 with whichthe teeth of the bars mesh. The gear 207 is mounted upon a vertical stub shaft 208 carried by the platform 110. Suitably mounted idler rollers 209 hold the teeth ,of the bars 206 in mesh with the gear 207. The outer ends of the bars 206 are attached to the carriages 112 and 113 by suitable connection providing for a certain amount of flexibility. In this device of my copending application the various movable elementsdescribed above comprise a parallel motion link age which serves to reproduce at the various tools the motion of the tracer over the template.

-sitiveness of the apparatus described in this copending application. may be increased by embodying thereinthe aspect of my. present invention which relates to insuring movement in unison of opposite members of the parallel motionlinkage independently of any lost motion that may occur within the parallel motion linkage. Accordingly in the embodiment of the invention illustrated in Fig. 8 I have provided means for operatively and positively connecting the two gear wheels 208 independently of the various membersof the parallel motion linkage. In Fig. 8 this function is performed b double cranks 301 rigidly affixed to each 0 the gear wheels 208, and connecting rods 302 and 303 which positively connect the double cranks in the same manner as described and illustrated for the structure shown in Fig. 5.

In Fig. 11 I have shown a different connecting means for the twogear Wheels 208 comprising rotary bevel gears 360 rigidly affixed to each of the gear wheels 208, and a 'rotatable shaft 361 provided with bevel gears 362 operatively connecting to the two bevel gear wheels 360.

In addition to these two methods of connecting the gear wheels 208 the rack bar connection illustrated in Fig. 1 may be utilized or the helical gear illustrated in Fig. 7 may be utilized and these latter forms of connection are to be deemed a part of this embodiment of the invention.

Whether utilized in a machine of the type illustrated in Fig. 1 or the type illustrated in Fig. 8 this feature of construction insures that opposite members of the parallel motion device, for example arms 15 and 15 of Fig. 1 or carriages 112, 113 and 112' and 113 of Fig. 8, will move instantaneously and equally in the operation of the device, independently of the presence of lost motion between certain of the links. Accordingly the higher degree of accuracy and sensitiveness is attained.

I claim:

1. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a. template, comprising a tracer, a reproducing tool, a main or base carriage, parallel motion linkage carried by said carriage and adapted to transmit motion from the tracer to the reproducing tool, two rotary members carried by said carriage and each operatively connected to an element of said linkage whereby the members rotate during change of position of said linkage with respect to the carriage, and means operatively connecting said two rotary members for causing them to rotate in unison.

2. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative toa template, comprising a tracer, a reproducing tool, a main or basecarriage, parallel motion linkage carried by said carriage and adapted to transmit motion from the tracer to the reproducing tool, two rotary members carried by said carriage and each operatively connected to an element of said linkage whereby the members rotate during change of position of said linkage with respect to the carriage, and means operatively connecting said two rotary members independently of the linkage for causing them to rotate in unison.

3. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a template, comprising a tracer, a reproducing tool, a main or base carriage, parallel motion linkage carried by said carriage and adapted to transmit motion from the tracer to the reproducing tool, two rotary members carried by said carriage and each operatively connected to an element of said linkage whereby the members rotate during change of position of said linkage with respect to the carriage, and means operatively connecting said two rotary members adjacent their axes independently of the linkage for causing them to rotate in unison.

4. A reproducing machine comprising a template follower device, a reproducin device, spaced arms for controlling said devices, means for supporting said arms to swing about parallel axes, and means kinematically interconnecting said arms adjacent their pivots to cause the arms to swing about their pivots in unison.

5. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a template, comprising a system of linkage including two pivotally mounted arms and a connecting link between said pivotally mounted arms and pivoted thereto, a rep-roducing tool controlled by said connecting link, a tracer adapted to actuate said system of linkage, and means for equalizing the angular movement of said pivotally mounted arms independently of lost motion in said system of linkage.

6. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a template, comprising a system of linkage including two pivotally mounted arms and a connecting link between said pivotally mounted arms and pivoted thereto, a reproducing tool controlled by said connecting link, a tracer adapted to actuate said system of linkage, rotary members rigidly connected respectively to the said pivotally mounted links for rotation therewith, and a connection between said rotary members for insuring equal angular rotation of the pivotally mounted arms independently of lost motion in the system of linkage.

7. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a template, comprising a movable carriage, parallel motion linkage having non-adj acent links rotatably mounted on said carriage about parallel spaced axes, a tracer operatively connected to said parallel motion linkage and a reproducing tool connected to said parallel motion linkage and adapted to be controlled thereby.

8. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a template, comprising a movable carriage, rot-atable links mounted on said carriage about spaced parallel axes, a lateral link connecting said rotatably mounted links, a tracer on one of the links and a reproducing tool on said lateral link.

9. A reproducing machine wherein the movement of the reproducing means in controlled by that of a tracer relative to a template, comprising a movable carriage, rotatable links mounted on said carriage about spaced parallel axes, lateral links connecting said rotatably mounted links and forming therewith a closed polygon, a tracer on one of the links and a reproducing tool on one of the'lateral links.

10. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a template, comprising a movable carriage, two laterally spaced parallel pivots on said carriage, rotatable links mounted on said carriage about the spaced parallel axes aflorded by said pivots, a lateral link connecting said rotatably mounted links and restraining them to parallel motion, a tracer on said lateral link and a reproducing tool on said lateral in z.

11. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a template, comprising a movable carriage, rotatable arms mounted on said carriage about spaced parallel axes, a lateral link connecting said rotatably mounted links and extending laterally on one side of said rotatably mounted links, a tracer on one of the links and a reproducing tool on said lateral link outside of said rotatably mounted arms.

12. A reproducing machine wherein the movement of the reproducing means is con trolled by that of a tracer relative to a template, comprising a movable carriage, parallel motion linkage comprising'links forming a closed polygon, non-adjacent links of said polygon being rotatably mounted on said carriage about spaced parallel axes, a tracer operatively connected to said parallel motion linkage and a reproducing tool connected to said parallel motion linkage and adap ed to be controlled/thereby. r

13. A reproducing machine wherein the movement of the reproducingmeans is controlled by that of a tracer relative to a template, comprising a movable carriage, parallel motion linkage associated with said carriage, non-adjacent members of said linkage being rotatably mounted on said carriage on spaced parallel pivots, a tracer operatively connected to said parallel motion linkage, a tool carried by said parallel motion linkage and adapted to be controlled by the movement of the tracer and means carried by the parallel motion linkage for balancing the weight of the tool with respect to said pivots.

14. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a template, comprising a movable carriage, rotatable arms mounted on said carriage about spaced parallel axes, a lateral link connecting said rotatably mounted arms and restraining them to parallel motion, a tracer on one of the links, a reproducing tool on said. lateral link, and a counterweight on said lat-erallink for balancing the reproducing tool laterally of the carriage.

15. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a template, comprising amovable carriage, rotatable links mounted on said carriage about spaced parallel axes, lateral links, one near each end of said rotatably mounted links, connecting said rotatably mounted links and restraining them to parallel motion, a tracer on one of the links, a reproducing tool on one of the lateral links, and a .counterweight on the other lateral link for balancing the reproducing tool longitudinally of the carriage.

16. A reproducing machine wherein the movement of the reproducing means is controlled by that of a tracer relative to a template, comprising a movable carriage, rotatable links mounted on said carriage about spaced parallel axes, a lateral link connecting said rotatably mounted links and extending laterally on one side of said rotatably mounted links, a pluralitv of reproducing tools and a counterweight adapted to balance the tools on said lateral link.

Signed by me at Boston, Massachusetts this seventh day of September, 1928.

. CARLOS KREBS. 

